Vaporization of JP-8 Jet Fuel in a Simulated Aircraft Fuel Tank ...

±1°F. A Brisk Heat 2,160 watt silicone rubber heating blanket measuring 36” x 36” was
mated to the bottom surface using RTV high temperature adhesive. An Omega
Engineering CN616 series 6-channel temperature controller limited the blanket
temperature. It had the capability to control the ramp up to a specified temperature and
maintain that within a few degrees.
Total hydrocarbon concentration within the ullage space was measured using a flame
ionization detector (FID) hydrocarbon analyzer. A Model VE7 heated total hydrocarbon
analyzer by J.U.M. engineering, shown in figure 3.3, was the analyzer used in the
experiments. FID’s can detect the concentration of hydrocarbons in a sample by burning
the sample in a hydrogen flame. When the sample is introduced into the hydrogen flame
an ionization process is initiated that releases free ions. An electrostatic field is created
by a high polarizing voltage applied to two electrodes near the burner. Positive ions
collect at the high voltage electrode and negative ions migrate to the collector electrode.
The current generated between the two electrodes is directly proportional to the amount
of hydrocarbons in the sample, and provides accurate total hydrocarbon measurements in
terms of a volumetric concentration relative to the calibration gas, in this case propane.
The burner oven is heated to 374°F so that no condensation of fuel vapor occurs
before reaching the flame. It is for this reason that heated sample lines and a sample
pump with heated heads were required to draw the sample from the tank to the analyzer.
Two Technical Heaters heated lines were used, 14’ and 4’, and maintained at 300°F by
Technical Heaters temperature controllers. An Air Dimensions, Inc. Dia-Vac dual heated
head pump was used to draw samples from sub-atmospheric pressures, as the FID’s built-
in sample pump could not maintain the required sample pressure for tests at low ambient
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